A variety of industrial and research applications require that ingredients, typically liquid, be dispensed into vessels or other types of receivers. Representative applications include formulation chemistry, mixing of dyes, pharmaceuticals, clinical research, genetic research, and combinatorial chemistry, to name a few.
It is desirable for a dispenser that is intended for these applications to be capable of:                dispensing one or more liquid ingredients into one or more receivers;        dispensing very small quantities of liquid (e.g., nano-liter to micro-liters);        dispensing liquid ingredients rapidly and accurately; and        monitoring the dispensing operation with real-time analysis and feedback.But few if any are. Rotary-type dispensers, wherein the dispensing elements or the receivers are moved in circular fashion, are well suited, at least in concept, to dispensing one or more ingredients onto or into one or more receivers. In fact, several prior-art dispensers have been developed that use rotary motion in conjunction with a dispensing operation.        
U.S. Pat. No. 6,192,945 B1 to Ford et al. discloses a fluid dispenser for an automated biological reaction system. The dispenser includes a circular reagent tray that supports reagent fluid dispensers. The reagent tray rotates to successively position individual fluid dispensers into a reagent delivery position over a slide. Once positioned, reagent is dispensed onto the slide and then a subsequent fluid dispenser is rotated into position.
U.S. Pat. No. 6,202,895 B1 to Fox discloses an apparatus for dispensing cosmetic foundation compositions. The apparatus includes a manually-rotatable carousel that receives a plurality of plunger-type dispensing elements. Various reagents (e.g., hair coloring, etc.) are stored in the dispensing elements. In use, the carousel is rotated to position a particular dispensing element over a mixing container. A desired amount of reagent is next dispensed into the mixing container. The carousel is then rotated to position another dispensing element over the mixing container, and so forth.
U.S. Pat. No. 6,338,820 B1 to Hubbard et al. discloses an apparatus for performing assays at reaction sites. The apparatus includes a rotatable substrate having radially-arrayed reaction sites. The apparatus further includes a rotary stepper motor that controllably rotates the substrate. The apparatus also has a dual-function head that includes a fluid dispenser for delivering fluid to a reaction site, as well as a sensor for receiving a signal from the reaction site. The dual-function head is suspended for linear movement across the rotatable substrate.
While illustrative of the manner in which rotary motion can be used in conjunction with a dispensing operation, the dispensers mentioned above are not capable of rapidly and accurately dispensing a plurality of ingredients into a plurality of receivers to create a plurality of formulations. In fact, few if any prior art dispensers, rotary or otherwise, are capable of providing this capability. Furthermore, it is very difficult to accurately dispense very small quantities of liquid or to monitor and correct the dispensing operation in real time.